Postoperative bleeding and the discharge of other fluid, herein referred to collectively as "body fluid," a volume of which may collect in the area of the wound under the theretofore dissected skin flaps, often results in complication of the healing process of the patient and may jeopardize the most carefully executed operative procedure.
For purposes of prevention of the collection of body fluid there have been developed over the years forms of pressure dressing as well as apparatus generally comprising a suction device and a perforated tube received within the tissue of the patient for fluidly connecting the suction device to the wound.
By removal of body fluid from the area of the wound during the first day or two after surgery thereby to maintain the wound in a relatively dry condition swelling may be reduced and medically favorable consequences such as the acceleration of the healing process may be expected.
The present invention is directed to the latter manner and means of postoperative treatment, constituting an improvement over apparatus of the prior art which comprises typically structures both illustrated and disclosed in Swiss Pat. No. 398,892; U.S. Pat. No. 3,115,138 to McElvenny et al.; and U.S. Pat. No. 3,376,868 to Mondiadis, assigned to the assignee of the present invention, now dedicated to the public.
Referring particularly to the Swiss patent, the apparatus includes a collection device having a pair of opposed walls separated by a pleated connecting wall which permits the opposed walls to be moved toward one another. This movement results in an evacuation of the chamber, creating as the opposed walls are moved apart to their original position a negative pressure condition therein. One of the walls sealingly supports a connecting tube which is adapted for connection to a drainage tube, a length of which is formed with a series of perforations through which the body fluid may enter at the situs of the wound. The other of the walls supports a weight whose downward force causes the walls to move apart. The resulting negative pressure of the chamber is communicated to the situs of the wound through the drainage tube and perforations. The Swiss device is stabilized by a hanger. The McElvenny et al. patent is generally similar in overall structure to that of the Swiss device except that it utilizes a series of springs disposed within and acting between opposed walls of the chamber to cause the opposed walls to separate.
The Mondiadis patent is a further representation of the prior art. To this end, Mondiadis discloses a container with a chamber, a connecting tube and a drainage tube for passing body fluid from the area of a wound into the chamber by virtue of the development of a negative pressure therein. In Mondiadis the container which is compressible is formed of a resilient elastomeric material whose memory when the forces are removed causes the walls to return to an uncompressed state as the body fluid is drawn therein through the flow path including the connecting tube.
While each of the apparatus discussed above have received varying degrees of acceptability the apparatus suffer from several disadvantages including ease and manner of operation, difficulty in discharging the fluid from the collecting container, accidentally causing the wound to be inflated, and the inability to maintain a relatively constant flow rate. Thus, the Swiss apparatus, for example, requires a hanger structure, a support for the hanger structure which may prevent ambulation of the patient, as well as a series of weights for developing a negative pressure. While both the apparatus of McElvenny et al. and Mondiadis do not prevent ambulation of the patient, they are adapted for securement on the body, they offer a degree of difficulty in evacuating air from the chamber through compression of the walls while at the same time controlling the port through which the air to be evacuated may pass and attaching a drainage and/or connecting tube to the container. Further, the McElvenny et al. apparatus requires a plurality of springs as described which add bulk to the structure and reduce the available interior space into which the body fluid is drawn. Further, the springs, as the weights in the Swiss apparatus, add unnecessary expense to the apparatus of this type which is disposable after use.